My big problem

I have big problem. I have a lot of unfinished pieces. They are really beautiful, most of them are better than pieces I've uploaded. I really don't know how to continue composing or when I get new idea, I will start new piece. And they are more and more... Do you have the same problem? What should I do?

This could be a wonderful problem for you.
I have another hobby which I have a bunch of start ups but not ready to finish yet.
If you are constantly coming up with new ideas, this can be good and you should not force yourself to finish everything directly.

My suggestion, which has worked well for me. . . . . .
Create a file system. Take your incomplete ideas and somehow file them.
You can file them by key, or by instrumentation, style, or perhaps assign them an idea like, "music for Fall", or "marches", "Lullabys", "small chamber", "colorful", "retrospective".

Perhaps the first weekend of each month you can slowly go through your files and see if anything speaks out to you. If not, leave it there and eventually one day you will be in the mood to finish it - or put that idea into another piece; Mahler did that.

This way when an idea comes to add more to a piece you can go pull from your file, add some notes, ideas, etc. Until the piece grows itself. Many authors, and composers have ideas they make note of and then don't complete until many years later. There is actually a mathematic formula that has been presented to account for "productive composing". In a nutshell you should be completing 75% of the compositions you start. If you complete more than that you are considered to be ignoring or losing ideas. IF you complete less than 75% then you might not be commiting yourself to your art. Of course this number can vary depending on the type of art, medium, quality of work.

Always generate ideas. Save them. Organize them in some way. Use those ideas as tools for YOU to use. Don't let the ideas get the better part of you.

Compositions sometimes are short pieces, sometimes long pieces; they can take a short time to write, take a long time to write...I've written an instrumental, and 25 years later came up with words.

A few years back when I discovered the Lilypond program I started to write my own compositions out - things I wrote in my early teens (mid 40's now) and college. Then I started to revisit old "incomplete" ieas, and new ones have always sprung up. My most productive time was when I was working the writing as a "craft" - I took a single theme and then put it through a "formula" and usually came up with a solid 4 to 5 minute piece.

Sometimes you have to work on being able to put the finished products together, and part of that is to not worry that everything you write has to be great. Sometimes the whole is more than the parts, and some of those parts might be downright simple. Most of my piano pieces end up having a LH voice that has a lot of whole notes. But combined with the other voice my LH plays there is a synergy.

Now - to your short "incomplete" pieces...if I had your issue and my experience, I'd look to make the pieces into short pieces, and try to write endings and bridges, and try to arrange some or all of into suites. You might learn some techniques, and find that some of your ideas fit together well. With many small pieces you might be able to coax several lager, more sophisticated works out of them.

I have had problems like these before as well. However, when I finished the, it usually came a couple weeks l;ater when I began to read them and look over them, trying to figure out what would sound good with it. I did for maybe 10-30 minutes, and then I got my idea on how to finish the piece. Although I have only had this problem 5 or 6 times, I have always managed to use this method and get new ideas on how to finish it. Hope that helps you out.